Some vehicles, particularly those which are used off-highway, employ a driving and steering axle; such vehicles are typically all wheel drive, and a steering axle may be at the front or at the back, or in both locations.
Necessarily a steering axle requires a track rod assembly to couple the pivotable wheel hubs of the axle, and this assembly may be connected to a conventional steering box, a steering rack, or a powered actuator responsive to movement of a steering wheel or the like.
In many off-highway vehicles, the range of wheel suspension movement is very large, and accordingly it is desirable to mount the track rod assembly, with respect to the corresponding axle, so as to avoid bump/steer effects which may occur with a track rod assembly mounted with respect to the vehicle body.
In one known arrangement a hydraulic barrel-type actuator is inserted in annular mounts of an axle, and has opposed track rods attached on the hub steering arms by conventional ball-jointed track rod ends. Such track rod ends typically comprise a female threaded body for attachment to a male threaded track rod, and a conventional taper pin for insertion through a tapered aperture of a steering arm; the taper pin includes a screw-threaded tip to receive a securing nut; the male/female attachment to the track rod may be reversed in some cases, and the taper pin may point up or down. The track rod assembly may be in front or behind the axle, with respect to the normal direction of vehicle movement.
During conventional assembly of the axle and hubs, the track rod actuator components are attached to the axle casing, and then the track rod ends are attached to the track rods before the taper pins are coupled to the respective steering arms. In a final step the threaded connection of track rod and track rod end is often adjusted to set the length of the track rod assembly, and hence the toe-in or toe-out of the wheels of the axle.
It would be desirable to provide a track rod assembly including attached track rod ends, to minimize attachment operations during vehicle assembly and to obviate delays due to problematic assembly and adjustment. However the radial extension (taper pin height) of a track rod end is typically greater than the bore of the annular mounts of the axle, so that insertion of a track rod assembly therethrough is obstructed.